The invention relates to a method and means for determining the subsurface position of a blowing well--from which fluids such as oil or gas escape in an uncontrolled manner--with respect to an adjacent relief well.
It is known in the art to stop the flow through a blowing well by drilling a relief well from a surface location near the blowing well. Such a relief well is drilled with the intention of intercepting the blowing well, preferably at a subsurface location near the downhole "source" location at which the fluids enter the wellbore at high velocity to enable the injection of water and/or weighted fluids via the relief well into the blowing well.
It is furthermore known in the art to make use of sound waves emanating from the blowing well to orient the drilling direction of the relief well towards the blowing well. U.S. Pat. No. 3,282,355 discloses an acoustic-wave receiving device that can be lowered into a relief well to detect acoustic waves emanating from an adjacent blowing well in order to obtain information on the positions of the wells relative to each other. U.S. Pat. No. 3,722,605 discloses an instrument for finding the radial direction of a blowing well with respect to a relief well. The instrument comprises a plurality of acoustic receivers mounted at various tangentially spaced locations on a tubular housing, which housing is inserted in, or forms part of, a non-rotating drill string located in the relief well. By comparing the arrival times of sound waves emanating from the blowing well at the tangentially spaced receivers an indication is obtained of the radial orientation of the blowing well relative to the relief well.
Although the known instruments may provide useful information on the position of the blowing well, these instruments are not able to indicate the position of this well in a sufficiently accurate manner.